2,657 research outputs found
Variable-camber systems integration and operational performance of the AFTI/F-111 mission adaptive wing
The advanced fighter technology integration, the AFTI/F-111 aircraft, is a preproduction F-111A testbed research airplane that was fitted with a smooth variable-camber mission adaptive wing. The camber was positioned and controlled by flexing the upper skins through rotary actuators and linkages driven by power drive units. The wing camber and control system are described. The measured servoactuator frequency responses are presented along with analytical predictions derived from the integrated characteristics of the control elements. A mission adaptive wing system chronology is used to illustrate and assess the reliability and dependability of the servoactuator system during 1524 hours of ground tests and 145 hours of flight testing
Virtual learning intervention to reduce bullying victimization in Primary School: a controlled trial
Background: Anti-bullying interventions to date have shown limited success in reducing victimization and have rarely been evaluated using a controlled trial design. This study examined the effects of the FearNot anti-bullying virtual learning intervention on escaping, and reducing
overall victimization rates among primary school students using a nonrandomized controlled trial design. The program was designed to enhance the coping skills of children who are known to be, or are likely to be, victimized.
Methods: One thousand one hundred twenty-nine children (mean age, 8.9 years) in twentyseven primary schools across the UK and Germany were assigned to the FearNot intervention or the waiting control condition. The program consisted of three sessions each lasting approximately 30 minutes over a three-week period. The participants were assessed on selfreport measures of victimization before and one and four weeks after the intervention or the
normal curriculum period.
Results: In the combined sample, baseline victims in the intervention group were more likely to escape victimization at the first follow-up compared with baseline victims in the control group (adjusted RR, 1.41; 95% CI, 1.02-1.81). A dose-response relationship between the amount of
active interaction with the virtual victims and escaping victimization was found (adjusted OR, 1.09; 95% CI, 1.003-1.18). Subsample analyses found a significant effect on escaping victimization only to hold for UK children (adjusted RR, 1.90; CI, 1.23-2.57). UK children in the
intervention group experienced decreased victimization rates at the first follow-up compared with controls, even after adjusting for baseline victimization, gender and age (adjusted RR, 0.60; 95% CI, 0.36-0.93).
Conclusions: A virtual learning intervention designed to help children experience effective strategies for dealing with bullying had a short-term effect on escaping victimization for a priori identified victims, and a short-term overall prevention effect for UK children.
Keywords: anti-bullying intervention, victimization, virtual learning, controlled trial
Abbreviation: FearNot: Fun with Empathic Agents to achieve Novel Outcomes in Teaching
Trial Registration: Clinical Trials Registry, NCT0059733
COVARIANCE ADJUSTMENT IN STUDIES INVOLVING OBSERVATIONAL FACTORS OR COVARIATES INFLUENCED BY TREATMENTS
We extend the definition of adjusted treatment means in the analysis of covariance to deal with the case where some of the covariates are influenced by treatments or where some of the factors are observational. In these cases, comparison of treatment means adjusted to a common value of the covariate may be inappropriate. Partially adjusted means are defined and it is shown that special cases include the usual adjusted means (adjusted to a common value for each of the covariates) and unadjusted means. In fact, in a multifactorial experiment, one can, by appropriate choice of adjustment, compare adjusted means for one factor but unadjusted means for the second factor. Partially adjusted means can be computed by any linear models software which will estimate linear combinations of the parameters
Charge Transfer Properties Through Graphene Layers in Gas Detectors
Graphene is a single layer of carbon atoms arranged in a honeycomb lattice
with remarkable mechanical, electrical and optical properties. For the first
time graphene layers suspended on copper meshes were installed into a gas
detector equipped with a gaseous electron multiplier. Measurements of low
energy electron and ion transfer through graphene were conducted. In this paper
we describe the sample preparation for suspended graphene layers, the testing
procedures and we discuss the preliminary results followed by a prospect of
further applications.Comment: 2014 IEEE Nuclear Science Symposium and Medical Imaging Conference
with the 21st Symposium on Room-Temperature Semiconductor X-Ray and Gamma-Ray
Detectors, 4 pages, 8 figure
Neutrality of narrative discussion in annual reports of UK listed companies
This paper reports the results of an investigation into the neutrality of the narrative discussion of financial performance and position, as evidenced in 179 annual reports of UK listed companies. Neutrality of narrative discussion was determined by comparing the average proportions of good and bad news contained in the narrative and statutory accounts sections of the annual reports. The results of a comparison of the proportion of good news in the two sections of the annual reports suggest that the narrative sections contained a significantly higher proportion of good news than the statutory accounts sections. Comparison of proportions of bad news, however, indicates that the narrative sections contained a significantly lower proportion of bad news compared to the statutory accounts sections. Finally, the results also suggest that the proportion of good news as compared to bad news in the narrative sections is significantly higher than the proportion of good news compared to bad news in the statutory accounts section. The results are consistent with the suggestion that company management highlights good news in narrative discussions. The implications of the findings for company management, users, auditors and regulators are discussed
Charge Transfer Properties Through Graphene for Applications in Gaseous Detectors
Graphene is a single layer of carbon atoms arranged in a honeycomb lattice
with remarkable mechanical and electrical properties. Regarded as the thinnest
and narrowest conductive mesh, it has drastically different transmission
behaviours when bombarded with electrons and ions in vacuum. This property, if
confirmed in gas, may be a definitive solution for the ion back-flow problem in
gaseous detectors. In order to ascertain this aspect, graphene layers of
dimensions of about 2x2cm, grown on a copper substrate, are transferred
onto a flat metal surface with holes, so that the graphene layer is freely
suspended. The graphene and the support are installed into a gaseous detector
equipped with a triple Gaseous Electron Multiplier (GEM), and the transparency
properties to electrons and ions are studied in gas as a function of the
electric fields. The techniques to produce the graphene samples are described,
and we report on preliminary tests of graphene-coated GEMs.Comment: 4pages, 3figures, 13th Pisa Meeting on Advanced Detector
Resolving the Origin of the Diffuse Soft X-ray Background
In January 1993, the Diffuse X-ray Spectrometer (DXS) measured the first high-resolution spectrum of the diffuse soft X-ray background between 44-80A. A line-dominated spectrum characteristic of a 10(exp 6)K collisionally ionized plasma' was expected but while the observed spectrum was clearly line-dominated, no model would fit. Then in 2003 the Cosmic Hot Interstellar Plasma Spectrometer (CHIPS) launched and observed the diffuse extreme-ultraviolet (EUV) spectrum between 90- 265A. Although many emission lines were again expected; only Fe IX at 171.1A was detected. The discovery of X-rays from comets led to the realization that heavy ions (Z=6-28) in the solar wind will emit soft X-rays as the ions interact via charge exchange with neutral atoms in the heliosphere and geocorona. Using a new model for solar wind charge exchange (SWCX) emission, we show that the diffuse soft X-ray background can be understood as a combination of emission from charge exchange onto the slow and fast solar wind together with a more distant and diffuse hot (10(exp 6)K) plasma
Joining the conspiracy? Negotiating ethics and emotions in researching (around) AIDS in southern Africa
AIDS is an emotive subject, particularly in southern Africa. Among those who have been directly affected by the disease, or who perceive themselves to be personally at risk, talking about AIDS inevitably arouses strong emotions - amongst them fear, distress, loss and anger. Conventionally, human geography research has avoided engagement with such emotions. Although the ideal of the detached observer has been roundly critiqued, the emphasis in methodological literature on 'doing no harm' has led even qualitative researchers to avoid difficult emotional encounters. Nonetheless, research is inevitably shaped by emotions, not least those of the researchers themselves. In this paper, we examine the role of emotions in the research process through our experiences of researching the lives of 'Young AIDS migrants' in Malawi and Lesotho. We explore how the context of the research gave rise to the production of particular emotions, and how, in response, we shaped the research, presenting a research agenda focused more on migration than AIDS. This example reveals a tension between universalised ethics expressed through ethical research guidelines that demand informed consent, and ethics of care, sensitive to emotional context. It also demonstrates how dualistic distinctions between reason and emotion, justice and care, global and local are unhelpful in interpreting the ethics of research practice
Explaining Opposition to Refugee Resettlement: The Role of NIMBYism and Perceived Threats
One week after President Donald Trump signed a controversial executive order to reduce the influx of refugees to the United States, we conducted a survey experiment to understand American citizens ’ attitudes toward refugee resettlement. Specifically, we evaluated whether citizens consider the geographic context of the resettlement program (that is, local versus national) and the degree to which they are swayed by media frames that increasingly associate refugees with terrorist thre ats. Our findings highlight a collective action problem: Participants are consistently less supportive of resettlement within their own communities than resettlement elsewhere in the country. This pattern holds across all measured demographic, political, and geographic subsamples within our data. Furthermore, our results demonstrate that threatening media frames significantly reduce support for both national and local resettlement. Conversely, media frames rebutting the threat posed by refugees have no sig- nificant effect. Finally, the results indicate that par ticipants in refugee-dense counties are less responsive to threatening frames, suggesting that proximity to previously settled refugees may reduce the impact of perceived security threats
Inter-cultural differences in response to a computer-based anti-bullying intervention
Background and purpose: Many holistic anti-bullying interventions have been attempted, with mixed success, while little work has been done to promote a 'self-help' approach to victimisation. The rise of the ICT curriculum and computer support in schools now allows for approaches that benefit from technology to be implemented. This study evaluates the cross-cultural effects of a computer-based anti-bullying intervention on primary school-aged children's knowledge about bullying and relevant coping strategies.
Programme description: FearNot! is an interactive computer-based virtual learning environment designed for use as an anti-bullying intervention. It includes interactive virtual agents who assume the most common participant roles found in episodes of bullying. FearNot! was used by children over three consecutive weeks to allow its effectiveness to be evaluated in a longitudinal in situ programme.
Sample: Two comparable samples were drawn from the UK and Germany. In the UK, 651 participants (aged 8-11) were recruited from primary schools in Hertfordshire, Coventry and Warwickshire, whereas the 535 German participants (aged 7-10) were sourced from Grundschulen in the Bayern and Hessen regions. Because of lack of parental consent, late joiners and absences/missing responses, data from 908 participants (UK 493; Germany 415) were analysed.
Design and methods: A quasi-experimental, pre/post-tests control group design employed pre-published and bespoke questionnaires to collect data. Descriptive and inferential analyses were conducted.
Results: UK students possessed higher coping strategy knowledge scores than German participants, but German children's scores improved over time and as a result of the FearNot! intervention.
Conclusions: Overall, while not effective at increasing children's coping strategy knowledge in this study, the FearNot! intervention could prove a useful classroom tool to approach the issue of bullying as part of a wider initiative. Cultural differences at baseline and reactions to the intervention are discussed
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